Roller head for a planetary rolling mill

ABSTRACT

A roller head for a planetary rolling arrangement, said roller head comprising a housing, inside which housing there is rotatably arranged a hollow outer axis and means for rotating said outer axis, as well as inside said outer axis, in a manner that transmits the rotary motion thereof, a center axis which is movable in the axial direction and can be locked in the axial direction, said center axis being provided with a roller. The roller head is characterized by an adjusting axis which is rotatably arranged at the end of the outer axis that is located on the opposite side with respect to the roller and is essentially locked in the axial direction said adjusting axis comprising a counterpart for the threaded section provided in the center axis, and said adjusting axis also including a locking member, which in the locking position forms a friction coupling at least between the adjusting axis and the outer axis.

[0001] The present invention relates to a roller head according to the preamble of claim 1.

[0002] Roller heads according to the object of the invention are used in planetary rolling arrangements, where the employed rolling members are mainly conical rollers. Typical prior art roller heads are introduced among others in the following patent publications: U.S. Pat. Nos. 3,718,020, 3,735,617 and 4,587,820. In certain practical applications of the roller heads according to the present invention, it is very important that the roller can be adjusted accurately in the axial direction. In known roller adjusting methods, a drawback is that said methods are very complicated, and/or that the axial adjustment of the roller is inaccurate owing to the employed coupling member arrangements of the adjusting apparatus. Prior art solutions have mainly utilized cogged coupling members for coupling the adjusting axis. Owing to the coupling arrangements of known solutions, the axial adjustment has become stepped. This has lead to a situation where the minimum quantity of the axially directed motional shift has been dependent on the cogging of the coupling member. Moreover, in prior art solutions, it has been troublesome to accurately measure the adjustment to be performed.

[0003] The object of the present invention is to achieve a completely new type of arrangement for enabling an advanced and more accurate method for performing the axial adjustment of a roller head. Another object of the invention is to achieve a roller head that enables the measurement of the axial adjustment in an easy and accurate manner.

[0004] The invention is characterized by what is stated in the accompanying claims.

[0005] The roller head according to the invention has several remarkable advantages. The adjusting arrangement according to the invention enables an extremely accurate and stepless axial adjustment. When applying a stepless locking of the adjusting axis, there is achieved a remarkably higher axial distance and centering accuracy for the rollers than in the prior art arrangements. By employing an expansible sleeve member as the locking member, there is achieved an extremely feasible solution for a locking member. By employing a pressure-operated sleeve member and particularly by employing a liquid as the pressure medium, said liquid being for instance hydraulic oil, there is achieved a suitable arrangement to be used in connection with the roller head. This solution enables a situation where the locking member constitutes a uniform piece with the adjusting member, or a situation where the locking member is a separate sleeve member between the adjusting axis and the outer axis.

[0006] The invention is explained in more detail below, with reference to the appended drawings, where

[0007]FIG. 1 illustrates a cross-section of a roller head according to the invention, and

[0008]FIG. 2 illustrates an enlarged detail A of FIG. 1.

[0009] The roller head illustrated in the drawings is a roller head used in the so-called PSW rolling mill (Planeten Schrägwalzwerk, planetary skew-rolling mill). Typically a PSW rolling mill includes three roller heads. The roller head 1 is arranged turnably in the rotor (not illustrated).

[0010] The roller head 1 according to the invention comprises a housing 8, inside which housing there is rotatably arranged a hollow outer axis 5 and means 2, 3, 4 for rotating said outer axis, as well as a center axis 6 arranged inside said outer axis, in a manner that transmits the rotary motion of said outer axis; said center axis 6 is movable in the axial direction and lockable in the axial direction, and it is also provided with a roller 7. In the operating axis 2 of the roller head, there is arranged a drive wheel 3, the rotary motion whereof is transmitted by means of a counterwheel 4 to the hollow outer axis 5 of the roller head. The outer axis 5 is arranged rotatably inside the housing 8 of the roller head 1 by intermediation of bearing members 9, 10, 11. The outer axis 6 of the roller head is rotatably arranged in the roller head housing, at least by two radial-thrust bearings 9, 11, and by an axial bearing 10 provided therebetween. Inside the outer axis 5, there is arranged a center axis 6 movably in the axial direction. On the inner surface of the outer axis 5, there are typically formed for example cogged coupling members 12, 13, in which case in the center axis 6, there are arranged counterparts that prevent the center axis 6 from rotating with respect to the outer axis 5, but allow the center axis to move in the axial direction. The roller 7 is arranged in the center axis 6. The roller head is characterized by an adjusting axis 16, which is arranged rotatably at that head of the outer axis 5 that is located at the opposite end with respect to the roller 7, said adjusting axis being essentially locked in the axial direction and comprising a counterpart 17 for the threaded section 15 provided in the center axis 6; said adjusting axis 16 includes a locking member 18, which in the locking position forms a friction coupling at least between the adjusting axis 16 and the outer axis 5. At that end of the center axis 6 that is located on the opposite side with respect to the roller 7, there is arranged a bore 14 with threadings 15 made in the side wall thereof. At that end of the roller head that is on the opposite side with respect to the roller 7, there is arranged an adjusting axis 16, comprising a counterpart 17 for the threaded section 15 of the center axis 6. The position of the center axis 6 in the axial direction can be adjusted by turning the adjusting axis 16. As a result, the position of the center axis 6 is changed for a distance determined by the thread of the threaded section and the counterpart, depending on the volume of the rotary motion of the adjusting axis. Typically the threads of the threaded section and the counterpart are extremely precise, for instance so-called trapezoidal threads. Typically the threaded section 15 of the center axis is arranged in a bore 14 made in the center axis, in which case the counterpart 17 of the adjusting axis is a screw member. The adjusting axis 16 comprises a locking member, such as a sleeve member, 18, whereby the adjusting axis can be steplessly locked in the outer axis 5. The locking member 18 is typically an expansible, pressure-operated sleeve member. In a preferred embodiment, the locking member 18 is a hydraulically operated sleeve member. In the embodiment according to the drawings, the locking member 18 constitutes a uniform piece with the adjusting axis 16. The locking member can also be a separate sleeve member located between the outer axis 5 and the adjusting axis 16. By means of the sleeve member 18, for instance the winding of the adjusting axis is prevented, and thus also the center axis 6 is locked in the axially adjusted position. Typically the adjusting axis 16 comprises members, such as shoulders 19, 20, in order to prevent it from shifting in the axial direction, at least during the adjusting process.

[0011]FIG. 2 shows part of the roller head in cross-section. FIG. 2 also shows a typical embodiment of the structure of the locking member 18. The locking member illustrated in the drawing is a so-called hydraulically operated sleeve member. There is arranged a fluid channel system 21, 22, 23 with some hydraulic fluid provided therein. When the liquid pressure in the channel system is raised, the sleeve 18 is at least partly expanded in the radial direction and attached, at the outer surface 18′, to the countersurface, which in the case according to the invention is the typically cylindrical surface 5′ located in the bore of the outer axis 5. In the embodiment illustrated in the drawing, in the adjusting axis 16 there is formed a liquid channel 23, provided with an adjusting screw 24, and by turning said screw the liquid pressure is raised or lowered in the channel system 21, 22, 23 of the sleeve member. In the arrangement according to the invention, the sleeve member 18 can form part of the adjusting axis 16, in which case it in the fastening position radially affects the outer axis 5 located outside said sleeve member, or it can be a separate sleeve member, in which case the sleeve member 18, by increasing pressure, radially affects the adjusting axis 16 located inside it, as well as the outer axis 5 located outside it.

[0012] The invention is operated so that the adjusting axis 16 is locked, while the rolling mill center axis 6 is adjusted at a desired point, to the outer axis 5 by means of the locking member 18, most suitably by a friction coupling, in which case also the center axis 6 is locked in the axial direction. In the case illustrated in FIG. 2, the expansive sleeve 18 serving as the locking member is pressurized by tightening the adjusting screw 24, so that the sleeve is expanded and forms a friction coupling. When the center axis should be adjusted in the axial direction, the adjusting screw 24 is screwed open, in which case the sleeve 18 is contracted and the friction coupling is released, and the adjusting axis 16 can again be turned. The axial motion of the rolling mill center axis 6 can be created and measured extremely accurately by providing, for the duration of the adjusting process, an installation device 25 coupled to a measuring device 26. The installation device includes a torsion shaft 27 comprising a counterpart 29 for the driver 28 of the adjusting axis 14. The volume of the axial motion of the center axis is obtained when the size of the rotary motion of the adjusting axis is measured. Advantageously the measuring device 26 is arranged to directly indicate the volume of the axial motion at a typical accuracy of for instance 0.01 mm.

[0013] By means of the roller head according to the invention, the axial adjustment is carried out more accurately than in the prior art. By employing an installation device provided with a measuring device, the adjusting process is carried out quickly and precisely. 

1. A roller head for a planetary rolling arrangement, said roller head (1) comprising a housing (8), inside which housing there is rotatably arranged a hollow outer axis (5) and means (2, 3, 4), for rotating said outer axis, as well as inside said outer axis, in a manner that transmits the rotary motion thereof, a center axis (6), which is movable in the axial direction and can be locked in the axial direction, said center axis (6) being provided with a roller (7), characterized by an adjusting axis (16) which is rotatably arranged at the head of the outer axis (5) that is at the opposite end with respect to the roller (7) and essentially locked in the axial direction, said adjusting axis (16) being provided with a counterpart (17) for a threaded section (15) arranged in the center axis (6) and said adjusting axis also comprising a locking member (18), which in the locking position forms a friction coupling at least between the adjusting axis (16) and the outer axis (5).
 2. A roller head according to claim 1, characterized in that said locking member (18) is an expansible, pressure-operated member.
 3. A roller head according to claim 1 or 2, characterized in that said locking member (18) is a hydraulically operated sleeve member.
 4. A roller head according to any of the claims 1-3, characterized in that said locking member (18) constitutes a uniform piece with the adjusting axis (16).
 5. A roller head according to any of the claims 1-3, characterized in that said locking member is a separate sleeve member placed in between the outer axis (5) and the adjusting axis (16).
 6. A roller head according to any of the claims 1-5, characterized in that the threaded section (15) of the center axis is arranged in a bore (14) made in the center axis, in which case the counterpart (17) of the adjusting axis is a screw member.
 7. A roller head according to any of the claims 1-6, characterized in that the adjusting axis (16) is in the adjusting position arranged to adjust an installation device (25), which comprises a measuring device (26).
 8. A roller head according to any of the claims 1-7, characterized in that the outer axis (6) is rotatably arranged in the roller head housing at least by two radial-thrust bearings (9, 11) and by an axial bearing (10) provided therebetween. 